26 



the removal of the anthers of the flowers does not in any way affect 

 the germination of the seeds. According to Ikeno (1910), Handel- 

 Mazzetti, in a monograph of the genus Taraxacum, states that hybrids 

 appear among the species of the genus. Therefore, normal fertil- 

 ization may be expected among certain species of Taraxacum. Ikeno 

 (1910) also reported that K. Tanaka, in unpublished results of some 

 work done in Japan during 1908 and 1909 in which Raunkiaer's 

 castration method was used, stated that T. albidum formed seeds 

 parthenogenetically while T. platycarpum did not. Later investi- 

 gations by Ikeno confirmed Tanaka's findings in that T. platycarpum 

 does not form seeds parthenogenetically, while in other forms of 

 Taraxacum both normal fertilization and parthenogenesis occur. 



All of the experiments and studies concerning seed production 

 made by the writer and herewith reported were made with Taraxacum 

 officinale Weber. During the month of May, in the years 1914 and 

 1915, a number of dandelion buds were enveloped within parchment 

 paper sacks just before they opened. At the time the heads on 

 the same and adjoining plants had produced seeds the sacks were 

 removed. Seeds apparently normal in size, color, and all other 

 respects were formed on the heads enveloped within the sacks, indi- 

 cating that parthenogenesis, cross-fertilization between flowers of 

 the same head, or self-fertilization had occurred. Some experiments 

 designed to test the effect of pollen from other dandelion flowers 

 yielded inconclusive results, tho giving some indication that fertili- 

 zation with pollen may occur. 



On May 26, 1919, a considerable number of dandelion plants 

 which still held unopened buds were located. With a sharp razor the 

 stamens and pistils together with the upper portion of the two sets 

 of green bracts were sliced off as close as possible to the ovary, and 

 then the head was enclosed in a parchment paper envelope which was 

 secured upright to a stake driven beside the plant. After a number 

 of plants were treated in this manner a series of buds were castrated 

 in like manner and left uncovered; that is, they were not enclosed 

 in envelopes. On June 5 both the bagged and unbagged heads 

 had produced seeds. The seeds from each head were collected in 

 separate bags and later (on June 11) placed in a germination chamber 

 along with separate lots of seeds from adjoining untreated seedhheads 

 which served as checks. The germination tests of these seeds 

 were made by placing them between sheets of blue blotting paper 



